Optical networks are increasingly complex and comprise a plurality of network components at different hierarchy levels. The components and equipment of the optical network have to be monitored against failures and outages. The increasing data traffic in the optical network requires a short reaction time and, if possible, a proactive exchange and/or repair of network equipment and/or network lines.
In a conventional optical network, typically, optical time domain reflectometry is employed to perform a diagnosis of transmission line failures within the optical network including fiber cuts, signal losses, and/or failure locations. Detected failures in transmission equipment lead to trouble reports when handled by support staff actions. In optical transport networks, warnings and alarms can be issued as events when parameters of the network's equipment exceed predetermined threshold levels. A network management system can be used for processing fault alarms and maintenance events following a predefined workflow event procedure. Multiple events, resulting e.g. from a single fault, can be combined or correlated by such a network management system to avoid a larger number of alarm messages or alarm events.
However, existing diagnostic and monitoring systems used in conventional optical networks can typically lead to high service downtimes due to the passive maintenance approach taken by these systems. Most conventional diagnostic and monitoring systems provide for a local fault identification on one network device or node but no global fault identification. This may lead to limited and/or incomplete troubleshooting for different stakeholders within the optical network. Further, customer's response time may be constrained due to lack of support staff and/or the unavailability of servicing equipment. Accordingly, there is a need to provide a method and apparatus for improving diagnostics and/or prognostics of a network behaviour of a complex hierarchical optical network.